1974 X chassis repair in the rear

Chris Obert

Chris Obert

autocrosser, X driver
I got most of my 11/1973 X disassembled today in preparation of doing the body & paint part of the restoration. One of the things I will do before paint is to reinforce the section that ties the rear struts together. Currently my project car has zero issues, but since the performance potential of the chassis suggests that this car will have much more power than stock...

Over the years I have seen lots of 1974 chassis failures, and some pretty interesting solutions to the failures, including Bertone's solution introduced for 1975. My question is if YOU have a suggested improvement solution, and what is it? A picture would be great... I don't need to reinvent the wheel if there is a 'best solution' already proven & understood.

I have a few weeks to think this one out, with a driver's school next Saturday, a race next Sunday, and a tech session on the 20 for Fiat America... So toss me some ideas so I can have a plan of attack!
 
Hi Chris,

do you have the italian book on the X1/9 with the yellow X on a green cover?
Came out a couple of years ago.
It has a pic of a red e1974 with a fabricated brace in the engine compartment that ties the area where the dogbone mounts to the chassis over to the left side strut tower.
If you don't have the book , I may be able to scan the pic for you next week.

On my own car, I haven't done anything...
 
No help here, just questions

Chris Obert said:
I
Over the years I have seen lots of 1974 chassis failures, and some pretty interesting solutions to the failures, including Bertone's solution introduced for 1975.
Click to expand...

What change was made in 1975? and what are the typical failures?
(I'm responsible for the welfare of a whole flock of '74s, and now I'm worried about my babies :))
 
Ulix said:
Hi Chris,

do you have the italian book on the X1/9 with the yellow X on a green cover?
Came out a couple of years ago.
It has a pic of a red e1974 with a fabricated brace in the engine compartment that ties the area where the dogbone mounts to the chassis over to the left side strut tower.
If you don't have the book , I may be able to scan the pic for you next week.

On my own car, I haven't done anything...
Click to expand...

I don't have the book so a scan when you have time would be great.
 
EricH said:
What change was made in 1975? and what are the typical failures?
(I'm responsible for the welfare of a whole flock of '74s, and now I'm worried about my babies :))
Click to expand...

The engine compartment rear/rear trunk front panel will break, usually starting at the top near the dog bone mount. I have also seen the panel seperate from a strut tower.
The factory solution was to reinforce the entire panel, just look at a 1975-88 car, the difference is obvious.
 
Pic

I suspect the load is fed into the silver and black thing, whatever that is...

p1120301.jpg
 
Racing solution

Here is a solution used on an old Kim Baker race car. It is not pretty, but it is strong!

Paul

 
Chris... Do you mean the strut towers...

... or below somewhere?

Are you looking for a STRUT BRACE of sorts???
 
Hi Tony,

look at Paul's pic.
The rear of the engine compartment, where the dogbone attaches, is very flimsy and weak on 1974 cars. When high engine torque really loads up this area of the top crossmember, things can get ugly and this area can become all mangled.
So the idea is to add some sort of brace to support the area of the body where the dogbone attaches.

On 1975 and later cars, this area was redesigned much stronger.
 
Ahhhh... Thanks Ulix...

Ya know... If it were me... I think I would build domething similar to the one pictured...



... but in COMBINATION with a cross tower strut brace. I think I would include "permanent" bolt on mounts, but then use a clevis and pin setup to easily lift and remove the brace for engine maintenance.
 
Chris Obert said:
The factory solution was to reinforce the entire panel, just look at a 1975-88 car, the difference is obvious.
Click to expand...

Does anyone have a good picture of this area on a newer car?

Can you post it here so I can get a hint of what I need to do with my -73 to strenghten it.

I just realised when I read this thread that I have seen some separation between the strut towers and the engine compartment rear/rear trunk front panel.

With the engine upgrade I did a few years back it is obvious I need to something about this pretty soon.

Many thanks to Chris for pointing this out to at least one ignorant X-owner.
 
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